Efficient tandem electrocatalysis: in situ exsolved Pd nanoparticles driving concurrent CO2 reduction and ethane oxidative dehydrogenation

Solid oxide electrolysis cells have emerged as a transformative technology for simultaneously converting CO 2 and oxidatively dehydrogenating ethane, enabling the co-production of value-added chemicals. Here, we report that in situ exsolved Pd nanoparticles on Sr 2 Fe 1.5 Mo 0.5 O 6-δ and Gd 0.1 Ce 0.9 O 2-δ surfaces significantly enhance catalytic activity for both CO 2 reduction and the oxidative dehydrogenation of ethane (ODE). The synergy of ODE-assisted electrolysis at 800 °C yields a remarkable 0.85 V decrease in operating voltage at 0.3 A cm –2 , demonstrating the superior thermodynamic advantage of the tandem system over standalone CO 2 reduction and lowering the energy consumption for CO production by 72.31%. Furthermore, the system achieves a peak ethylene yield of 82.23% under practical conditions (0.3 A cm –2 , 800 °C, C 2 H 6 flow rate of 15 mL min –1 , and CO 2 flow rate of 30 mL min –1 ), ranking among the highest reported to date. In situ Raman spectroscopy reveals that oxygen species generated during CO 2 electrolysis are effectively pumped to the air electrode, acting as active oxidants that drive the synergistic oxidation process. Density functional theory simulations combined with experimental results further indicate that the exsolved Pd nanoparticles possess enhanced C 2 H 6 adsorption and lower the dehydrogenation energy barrier, thereby promoting C 2 H 4 formation.